Types of general equipment valves

(1) Threaded connection valve
This connection is usually achieved by processing the inlet and outlet ends of the valve into tapered or straight pipe threads that can be connected to tapered pipe threaded joints or pipes. Since this connection may have large leakage channels, sealant, sealing tape or packing can be used to block these channels. If the valve body material is weldable, but the expansion coefficient is very different, or the operating temperature range is large, the threaded connection must be honey sealed. The threaded valve is a valve with a nominal diameter less than 50 mm. If the diameter is too large, it is difficult to install and seal the connecting parts. In order to facilitate the installation and removal of threaded valves, pipe fittings are provided at appropriate positions in the piping system. Valves with a nominal diameter of less than 50 mm can be connected by a casing joint. The threads of the casing joint connect the two components together.
(2) The flange valve is
easy to install and disassemble. But they are heavier and more expensive than threaded valves. Therefore, it is suitable for pipe connections of various diameters and pressures. However, when the temperature exceeds 350 degrees, the bolts, gaskets, and flanges become loose, which greatly reduces the load of the bolts. Applying strong force to the flange connection may cause leakage.
(3) Welded connection valve
This connection method is suitable for all pressures and temperatures, and is more reliable than flange connection when used under more load conditions. But welded valves are difficult to disassemble and reinstall, so their use is limited to long-term reliable operation, or under stress and high temperatures. Such as thermal power plants, nuclear power projects, ethylene engineering pipelines, etc. Welded valves with a nominal diameter of less than 50 mm usually have a welding sleeve for carrying the pipe at the end of the loading plane. Socket welding Since the gap between the socket and the pipe is formed during the socket welding process, the gap may be corroded by a certain medium, and the vibration of the pipe may cause joint fatigue, so the use of socket welding is restricted. In the case of large nominal diameter, high temperature, and harsh working conditions, the valve body usually adopts groove welding, requiring in-situ welding of the weld.